The use of paint stripes on road surfaces is the accepted method to indicate vehicle lanes, crossing lanes, parking areas and numerous other indicators. Various pavement marking techniques are well known in the art, including the use of traffic paint, thermoplastics, epoxy paints and preformed tapes. Most pavement marking systems are intended to be as durable and permanent as possible, and resistant to weathering and wear from traffic. Common road surfaces are asphalt and concrete. The removal of such striping is typically required when the road is to be resurfaced or if the indication is to be changed.
When polymers such as paint or plastic are used for roadway marking, the surface of the pavement is penetrated from ⅛-⅜ inch, so that mere surface removal of the marking material is not sufficient to remove the marking. Therefore, current pavement marking removal machines often employ various forms of cutting devices to remove the marking material, as well as a portion of the underlying layer of pavement material in order to effectively remove painted lines.
Commonly known methods for removal of such markings typically include the use of abrasive grinding wheels, material removing cutters, or blasting of abrasive particles against the material to be removed. However, the use of these devices often results in undesirable grooves in the pavement surface.
It is also known in the art of marking removal to utilize high pressure water to remove road markings and the like. For example, U.S. Pat. No. 5,078,161 to Raghaven et al. discloses a method of cleaning an airport runway utilizing ultra high pressure water. The device disclosed by Raghaven includes a rotatably mounted spray bar. A hollow conduit extends to the spray bar through which the high pressure water is supplied to the spray bar. A hydraulic motor and belt are utilized to rotate the hollow conduit and the spray bar simultaneously. A drawback to this configuration is component failure and wasted energy. Belts or chains are prone to breakage and require additional maintenance. The use of a gear train between the motor and the conduit requires precision mounting points for alignment significantly increasing the cost of the assembly.
Therefore, what is needed in the art is a high pressure water blasting head having a hydraulic motor with a tubular output shaft. The tubular output shaft should be constructed and arranged to directly rotate at least one device, preferably a spray bar, with a first pressurized fluid while allowing the passage of a second fluid through the pump via the output shaft to supply the second fluid to the rotated device.